CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the handling of non-linear socket buffers (skbs) in the context of Generic XDP, where improper length accounting can lead to the disclosure of sensitive data, including kernel pointers, to userspace. This flaw can result in corrupted UDP payloads, potentially allowing an attacker to manipulate or intercept data. Organizations using Linux systems, particularly those leveraging XDP for high-performance packet processing, should prioritize applying the fix to mitigate the risk of data leakage and ensure the integrity of network communications.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: net: fix skb length accounting after generic XDP frag adjustment Generic XDP exposes non-linear skb fragments through an xdp_buff. If an XDP program adjusts the fragment area, bpf_prog_run_generic_xdp() copies xdp_frags_size back to skb->data_len but leaves skb->len containing the old fragment contribution. After a fragment shrink, this makes skb_headlen() larger than the actual linear area. In the reproduced UDP receive path, __skb_datagram_iter() copied 1024 bytes past the actual linear tail to userspace, starting at struct skb_shared_info. The copied bytes included the affected skb's nr_frags, xdp_frags_size and a kernel pointer from skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same amount and truncated at the end. Subtract the old data_len before replacing it and add the new data_len afterwards, keeping skb->len and skb->data_len synchronized. A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by 1024 bytes from its fragment area. Before the fix, all 10 runs produced corrupted payloads. After the fix, all 10 runs matched the expected payload exactly.